/*
 *   ownCloud Android client application
 *
 *   @author David A. Velasco
 *   @author Chris Narkiewicz
 *
 *   Copyright (C) 2016  ownCloud Inc.
 *   Copyright (C) 2019 Chris Narkiewicz <hello@ezaquarii.com>
 *
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License version 2,
 *   as published by the Free Software Foundation.
 *
 *   This program is distributed in the hd that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */
package com.owncloud.android.ui.preview;

import android.annotation.SuppressLint;
import android.content.BroadcastReceiver;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.ServiceConnection;
import android.graphics.Color;
import android.os.Bundle;
import android.os.IBinder;
import android.view.MenuItem;
import android.view.View;

import com.nextcloud.client.account.User;
import com.nextcloud.client.di.Injectable;
import com.nextcloud.client.preferences.AppPreferences;
import com.nextcloud.java.util.Optional;
import com.owncloud.android.MainApp;
import com.owncloud.android.R;
import com.owncloud.android.datamodel.FileDataStorageManager;
import com.owncloud.android.datamodel.OCFile;
import com.owncloud.android.datamodel.VirtualFolderType;
import com.owncloud.android.files.services.FileDownloader;
import com.owncloud.android.files.services.FileDownloader.FileDownloaderBinder;
import com.owncloud.android.files.services.FileUploader;
import com.owncloud.android.files.services.FileUploader.FileUploaderBinder;
import com.owncloud.android.lib.common.operations.OnRemoteOperationListener;
import com.owncloud.android.lib.common.operations.RemoteOperation;
import com.owncloud.android.lib.common.operations.RemoteOperationResult;
import com.owncloud.android.lib.common.utils.Log_OC;
import com.owncloud.android.operations.RemoveFileOperation;
import com.owncloud.android.operations.SynchronizeFileOperation;
import com.owncloud.android.ui.activity.FileActivity;
import com.owncloud.android.ui.activity.FileDisplayActivity;
import com.owncloud.android.ui.fragment.FileFragment;
import com.owncloud.android.utils.MimeTypeUtil;
import com.owncloud.android.utils.theme.ThemeToolbarUtils;

import java.io.Serializable;

import javax.inject.Inject;

import androidx.annotation.NonNull;
import androidx.appcompat.app.ActionBar;
import androidx.drawerlayout.widget.DrawerLayout;
import androidx.localbroadcastmanager.content.LocalBroadcastManager;
import androidx.viewpager.widget.ViewPager;
import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;


/**
 *  Holds a swiping galley where image files contained in an Nextcloud directory are shown
 */
@SuppressWarnings("PMD.AvoidDuplicateLiterals")
public class PreviewImageActivity extends FileActivity implements
        FileFragment.ContainerActivity,
        ViewPager.OnPageChangeListener,
        OnRemoteOperationListener,
        Injectable {

    public static final String TAG = PreviewImageActivity.class.getSimpleName();
    public static final String EXTRA_VIRTUAL_TYPE = "EXTRA_VIRTUAL_TYPE";
    private static final String KEY_WAITING_FOR_BINDER = "WAITING_FOR_BINDER";
    private static final String KEY_SYSTEM_VISIBLE = "TRUE";

    private ViewPager mViewPager;
    private PreviewImagePagerAdapter mPreviewImagePagerAdapter;
    private int mSavedPosition;
    private boolean mHasSavedPosition;
    private boolean mRequestWaitingForBinder;
    private DownloadFinishReceiver mDownloadFinishReceiver;
    private View mFullScreenAnchorView;
    @Inject AppPreferences preferences;
    @Inject LocalBroadcastManager localBroadcastManager;

    public static Intent previewFileIntent(Context context, User user, OCFile file) {
        final Intent intent = new Intent(context, PreviewImageActivity.class);
        intent.putExtra(FileActivity.EXTRA_FILE, file);
        intent.putExtra(FileActivity.EXTRA_USER, user);
        return intent;
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        final ActionBar actionBar = getSupportActionBar();

        if (savedInstanceState != null && !savedInstanceState.getBoolean(KEY_SYSTEM_VISIBLE, true) &&
            actionBar != null) {
            actionBar.hide();
        }

        setContentView(R.layout.preview_image_activity);

        // Navigation Drawer
        setupDrawer();

        // ActionBar
        updateActionBarTitleAndHomeButton(null);

        ThemeToolbarUtils.tintBackButton(actionBar, this, Color.WHITE);

        mFullScreenAnchorView = getWindow().getDecorView();
        // to keep our UI controls visibility in line with system bars visibility
        setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED);

        if (savedInstanceState != null) {
            mRequestWaitingForBinder = savedInstanceState.getBoolean(KEY_WAITING_FOR_BINDER);
        } else {
            mRequestWaitingForBinder = false;
        }

    }

    private void initViewPager(User user) {
        // virtual folder
        final Serializable virtualFolderType = getIntent().getSerializableExtra(EXTRA_VIRTUAL_TYPE);
        if (virtualFolderType != null && virtualFolderType != VirtualFolderType.NONE) {
            VirtualFolderType type = (VirtualFolderType) virtualFolderType;

            mPreviewImagePagerAdapter = new PreviewImagePagerAdapter(getSupportFragmentManager(),
                                                                     type,
                                                                     user,
                                                                     getStorageManager());
        } else {
            // get parent from path
            OCFile parentFolder = getStorageManager().getFileById(getFile().getParentId());

            if (parentFolder == null) {
                // should not be necessary
                parentFolder = getStorageManager().getFileByPath(OCFile.ROOT_PATH);
            }

            mPreviewImagePagerAdapter = new PreviewImagePagerAdapter(
                getSupportFragmentManager(),
                parentFolder,
                user,
                getStorageManager(),
                MainApp.isOnlyOnDevice(),
                preferences
            );
        }

        mViewPager = findViewById(R.id.fragmentPager);

        int position = mHasSavedPosition ? mSavedPosition : mPreviewImagePagerAdapter.getFilePosition(getFile());
        position = position >= 0 ? position : 0;

        mViewPager.setAdapter(mPreviewImagePagerAdapter);
        mViewPager.addOnPageChangeListener(this);
        mViewPager.setCurrentItem(position);

        if (position == 0 && !getFile().isDown()) {
            // this is necessary because mViewPager.setCurrentItem(0) just after setting the
            // adapter does not result in a call to #onPageSelected(0)
            mRequestWaitingForBinder = true;
        }
    }

    @Override
    public void onStart() {
        super.onStart();
        Optional<User> optionalUser = getUser();
        if (optionalUser.isPresent()) {
            OCFile file = getFile();
            /// Validate handled file (first image to preview)
            if (file == null) {
                throw new IllegalStateException("Instanced with a NULL OCFile");
            }
            if (!MimeTypeUtil.isImage(file)) {
                throw new IllegalArgumentException("Non-image file passed as argument");
            }

            // Update file according to DB file, if it is possible
            if (file.getFileId() > FileDataStorageManager.ROOT_PARENT_ID) {
                file = getStorageManager().getFileById(file.getFileId());
            }

            if (file != null) {
                /// Refresh the activity according to the Account and OCFile set
                setFile(file);  // reset after getting it fresh from storageManager
                getSupportActionBar().setTitle(getFile().getFileName());
                //if (!stateWasRecovered) {
                initViewPager(optionalUser.get());
                //}

            } else {
                // handled file not in the current Account
                finish();
            }
        }
    }

    @Override
    protected void onSaveInstanceState(@NonNull Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putBoolean(KEY_WAITING_FOR_BINDER, mRequestWaitingForBinder);
        outState.putBoolean(KEY_SYSTEM_VISIBLE, isSystemUIVisible());
    }

    @Override
    public void onRemoteOperationFinish(RemoteOperation operation, RemoteOperationResult result) {
        super.onRemoteOperationFinish(operation, result);

        if (operation instanceof RemoveFileOperation) {
            finish();
        } else if (operation instanceof SynchronizeFileOperation) {
            onSynchronizeFileOperationFinish(result);
        }
    }

    private void onSynchronizeFileOperationFinish(RemoteOperationResult result) {
        if (result.isSuccess()) {
            supportInvalidateOptionsMenu();
        }
    }

    @Override
    protected ServiceConnection newTransferenceServiceConnection() {
        return new PreviewImageServiceConnection();
    }

    /** Defines callbacks for service binding, passed to bindService() */
    private class PreviewImageServiceConnection implements ServiceConnection {

        @Override
        public void onServiceConnected(ComponentName component, IBinder service) {

            if (component.equals(new ComponentName(PreviewImageActivity.this,
                    FileDownloader.class))) {
                mDownloaderBinder = (FileDownloaderBinder) service;
                if (mRequestWaitingForBinder) {
                    mRequestWaitingForBinder = false;
                    Log_OC.d(TAG, "Simulating reselection of current page after connection " +
                            "of download binder");
                    onPageSelected(mViewPager.getCurrentItem());
                }

            } else if (component.equals(new ComponentName(PreviewImageActivity.this,
                    FileUploader.class))) {
                Log_OC.d(TAG, "Upload service connected");
                mUploaderBinder = (FileUploaderBinder) service;
            }

        }

        @Override
        public void onServiceDisconnected(ComponentName component) {
            if (component.equals(new ComponentName(PreviewImageActivity.this,
                    FileDownloader.class))) {
                Log_OC.d(TAG, "Download service suddenly disconnected");
                mDownloaderBinder = null;
            } else if (component.equals(new ComponentName(PreviewImageActivity.this,
                    FileUploader.class))) {
                Log_OC.d(TAG, "Upload service suddenly disconnected");
                mUploaderBinder = null;
            }
        }
    }


    @Override
    public void onStop() {
        super.onStop();
    }


    @Override
    public void onDestroy() {
        super.onDestroy();
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        boolean returnValue = false;

        switch(item.getItemId()){
        case android.R.id.home:
            if (isDrawerOpen()) {
                closeDrawer();
            } else {
                backToDisplayActivity();
            }
            returnValue = true;
            break;
        default:
        	returnValue = super.onOptionsItemSelected(item);
            break;
        }

        return returnValue;
    }


    @Override
    protected void onResume() {
        super.onResume();

        mDownloadFinishReceiver = new DownloadFinishReceiver();

        IntentFilter filter = new IntentFilter(FileDownloader.getDownloadFinishMessage());
        filter.addAction(FileDownloader.getDownloadAddedMessage());
        localBroadcastManager.registerReceiver(mDownloadFinishReceiver, filter);
    }

    @Override
    protected void onPostResume() {
        super.onPostResume();
    }

    @Override
    public void onPause() {
        if (mDownloadFinishReceiver != null){
            localBroadcastManager.unregisterReceiver(mDownloadFinishReceiver);
            mDownloadFinishReceiver = null;
        }

        super.onPause();
    }


    private void backToDisplayActivity() {
        finish();
    }

    @SuppressFBWarnings("DLS")
    @Override
    public void showDetails(OCFile file) {
        final Intent showDetailsIntent = new Intent(this, FileDisplayActivity.class);
        showDetailsIntent.setAction(FileDisplayActivity.ACTION_DETAILS);
        showDetailsIntent.putExtra(FileActivity.EXTRA_FILE, file);
        showDetailsIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        startActivity(showDetailsIntent);
        finish();
    }

    @Override
    public void showDetails(OCFile file, int activeTab) {
        showDetails(file);
    }

    public void requestForDownload(OCFile file) {
        if (mDownloaderBinder == null) {
            Log_OC.d(TAG, "requestForDownload called without binder to download service");

        } else if (!mDownloaderBinder.isDownloading(getUserAccountManager().getUser(), file)) {
            final User user = getUser().orElseThrow(RuntimeException::new);
            Intent i = new Intent(this, FileDownloader.class);
            i.putExtra(FileDownloader.EXTRA_USER, user);
            i.putExtra(FileDownloader.EXTRA_FILE, file);
            startService(i);
        }
    }

    /**
     * This method will be invoked when a new page becomes selected. Animation is not necessarily
     * complete.
     *
     *  @param  position        Position index of the new selected page
     */
    @Override
    public void onPageSelected(int position) {
        mSavedPosition = position;
        mHasSavedPosition = true;
        if (mDownloaderBinder == null) {
            mRequestWaitingForBinder = true;
        } else {
            OCFile currentFile = mPreviewImagePagerAdapter.getFileAt(position);

            if (currentFile != null) {
                if (getSupportActionBar() != null) {
                    getSupportActionBar().setTitle(currentFile.getFileName());
                }
                setDrawerIndicatorEnabled(false);

                if (currentFile.isEncrypted() && !currentFile.isDown() &&
                        !mPreviewImagePagerAdapter.pendingErrorAt(position)) {
                    requestForDownload(currentFile);
                }

                // Call to reset image zoom to initial state
                // ((PreviewImagePagerAdapter) mViewPager.getAdapter()).resetZoom();
            }
        }

    }

    /**
     * Called when the scroll state changes. Useful for discovering when the user begins dragging,
     * when the pager is automatically settling to the current page. when it is fully stopped/idle.
     *
     * @param   state       The new scroll state (SCROLL_STATE_IDLE, _DRAGGING, _SETTLING
     */
    @Override
    public void onPageScrollStateChanged(int state) {
        // not used at the moment
    }

    /**
     * This method will be invoked when the current page is scrolled, either as part of a
     * programmatically initiated smooth scroll or a user initiated touch scroll.
     *
     * @param   position                Position index of the first page currently being displayed.
     *                                  Page position+1 will be visible if positionOffset is
     *                                  nonzero.
     * @param   positionOffset          Value from [0, 1) indicating the offset from the page
     *                                  at position.
     * @param   positionOffsetPixels    Value in pixels indicating the offset from position.
     */
    @Override
    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
        // not used at the moment
    }

    /**
     * Class waiting for broadcast events from the {@link FileDownloader} service.
     *
     * Updates the UI when a download is started or finished, provided that it is relevant for the
     * folder displayed in the gallery.
     */
    private class DownloadFinishReceiver extends BroadcastReceiver {
        @Override
        public void onReceive(Context context, Intent intent) {
            String accountName = intent.getStringExtra(FileDownloader.ACCOUNT_NAME);
            String downloadedRemotePath = intent.getStringExtra(FileDownloader.EXTRA_REMOTE_PATH);
            if (getAccount().name.equals(accountName) &&
                    downloadedRemotePath != null) {

                OCFile file = getStorageManager().getFileByPath(downloadedRemotePath);
                int position = mPreviewImagePagerAdapter.getFilePosition(file);
                boolean downloadWasFine = intent.getBooleanExtra(FileDownloader.EXTRA_DOWNLOAD_RESULT, false);
                //boolean isOffscreen =  Math.abs((mViewPager.getCurrentItem() - position))
                // <= mViewPager.getOffscreenPageLimit();

                if (position >= 0 && intent.getAction().equals(FileDownloader.getDownloadFinishMessage())) {
                    if (downloadWasFine) {
                        mPreviewImagePagerAdapter.updateFile(position, file);

                    } else {
                        mPreviewImagePagerAdapter.updateWithDownloadError(position);
                    }
                    mPreviewImagePagerAdapter.notifyDataSetChanged();   // will trigger the creation of new fragments
                } else {
                    Log_OC.d(TAG, "Download finished, but the fragment is offscreen");
                }
            }
        }
    }

    public boolean isSystemUIVisible() {
        return getSupportActionBar() == null || getSupportActionBar().isShowing();
    }

    public void toggleFullScreen() {
        boolean visible = (mFullScreenAnchorView.getSystemUiVisibility()
                & View.SYSTEM_UI_FLAG_HIDE_NAVIGATION) == 0;

        if (visible) {
            hideSystemUI(mFullScreenAnchorView);
            // actionBar.hide(); // propagated through
            // OnSystemUiVisibilityChangeListener()
        } else {
            showSystemUI(mFullScreenAnchorView);
            // actionBar.show(); // propagated through
            // OnSystemUiVisibilityChangeListener()
        }
    }

    public void switchToFullScreen() {
        hideSystemUI(mFullScreenAnchorView);
    }

    @Override
    public void onBrowsedDownTo(OCFile folder) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onTransferStateChanged(OCFile file, boolean downloading, boolean uploading) {
        // TODO Auto-generated method stub

    }


    @SuppressLint("InlinedApi")
	private void hideSystemUI(View anchorView) {
        anchorView.setSystemUiVisibility(
                View.SYSTEM_UI_FLAG_HIDE_NAVIGATION         // hides NAVIGATION BAR; Android >= 4.0
            |   View.SYSTEM_UI_FLAG_FULLSCREEN              // hides STATUS BAR;     Android >= 4.1
            |   View.SYSTEM_UI_FLAG_IMMERSIVE               // stays interactive;    Android >= 4.4
            |   View.SYSTEM_UI_FLAG_LAYOUT_STABLE           // draw full window;     Android >= 4.1
            |   View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN       // draw full window;     Android >= 4.1
            |   View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION  // draw full window;     Android >= 4.1
        );
    }

    @SuppressLint("InlinedApi")
    private void showSystemUI(View anchorView) {
        anchorView.setSystemUiVisibility(
                View.SYSTEM_UI_FLAG_LAYOUT_STABLE           // draw full window;     Android >= 4.1
            |   View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN       // draw full window;     Android >= 4.1
            |   View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION  // draw full window;     Android >= 4.
        );
    }
}
